The project goal is to investigate the hydrology, geochemistry, microbiology, geology, and ecosystem dynamics of two oilfield sites impacted with produced water and associated oil and chemicals. The ultimate goal is to generate a credible analysis to understand the fate of trace hydrocarbons and the related ecosystem interaction.
U.S. Geological Survey
Menlo Park, CA
U.S. Environmental Protection Agency
Bureau of Indian Affairs (BIA)
Osage Environmental Office
Sound and unbiased studies are needed to evaluate the long- and short-term effects of hydrocarbons and the dissolved and suspended constituents of produced water on soil and ground and surface water and the natural processes that may be mitigating effects at older sites and at currently active ones. Two oil and gas production research sites have been selected adjacent Skiatook Lake in the southeastern Osage Reservation in northeastern Oklahoma. The Osage Nation holds the mineral rights, the BIA has trust responsibility, and the U.S. Army Corps of Engineers owns the surface at these sites.
The geologic and climatic settings of these two sites resemble that of much of the major southern Midcontinent oil- and gas-producing area of the U.S. Oil and gas production has occurred in this area for over 100 years. Thus the fields provide an opportunity for a study of the long-term effects of produced water on soils, water, and vegetation.
The project evaluated long-term and short-term effects of hydrocarbons and dissolved and suspended constituents of produced water on soil, groundwater, and surface water. Researchers examined mitigation effects of natural processes at older sites and active sites for comparing and evaluating the rate of soil recovery.
Investigation of the hydrology, geochemistry, microbiology, geology, and ecosystem dynamics in oilfield site contamination will provide better remediation practices through an understanding of the fate and ecosystem interactions of organic and inorganic contaminants at these research sites and thus will apply to similar sites.
This is a multi-disciplinary, multi-agency investigation. Actual work includes the following detailed characterizations:
Reconnaissance examination of the two sites shows that local effects include soil salinization with resultant destruction of soil textures and deep erosion, death of proximal vegetation and stress on peripheral vegetation, salinization of surface water and groundwater, saturation of soils with crude oil of varying age, and weathering and dispersal of crude oil components and trace elements.
Work included mapping and characterization of geologic, geophysical, vegetation, and soil resources and sampling and analysis of oil, gas, and produced water sources. Fifty sampling wells were drilled to delineate produced water and hydrocarbon sources, collect samples, and develop transport models for geochemical and microbial toxins. Additional samples were taken from the wells several months after the first collection to allow study of short-term changes and seasonal differences. The analysis was used to assess the signatures of disturbed and undisturbed sites, the geochemical impacts on oak trees, the recovery of oak forest ecosystems, and the interchange between the water and sediments in the reservoir and the contaminated surface water and groundwater. Researchers analyzed changes in the soil and water with respect to oil saturation and trace elements and the impact on local fish species.
The project received a no-cost extension to September 30, 2006 to complete all reporting requirements. The project activities are complete.
$830,000 (85.4% of total)